Simple number manipulation by macro help

Hello, firstly many thanks for taking the time to view my problem. I have to say i think this might be the simplest problem i have put on here.

Essentially all i am aiming to do is manipulate numbers in multiple datasets via a macro. I am aware that this could be done via formulae very easily, however due to the nature of the spreadsheet this is not the best option.

I have attatched a simple example spreadsheet to clarify the problem.

Again many thanks for your time.

Alan